1. Field of the Invention
The present invention relates to lasers and, more particularly, to a laser-pumped, thulium-doped YALO solid state laser capable of producing a desired wavelength having a shallow absorption depth in human and animal tissue without the use of a tuning element.
2. Description of the Related Art
Solid-state lasers doped with thulium (Tm.sup.3+) have demonstrated tunability over a range of wavelengths as disclosed, for example, in U.S. Pat. No. 4,969,150 which is incorporated herein by reference. These lasers are useful for medical applications because they can be tuned to wavelengths where tissue (which is predominantly water) has a shallow absorption depth. FIG. 1 illustrates a curve plotting absorption depth in water for various wavelengths of light. For medical applications, the most shallow absorption depth is preferred. Holmium:YAG (Ho:YAG) and thulium:YAG (Tm:YAG) lasers are currently used for medical applications. A new type of laser capable of reliably operating at a wavelength having a shallow absorption depth is desired.